This invention relates to a process for producing a microoptical functional unit which includes at least two interconnected parts each of which have at least one optical functional element, for production at least two flat parts being provided with a number of optically functional sections. The flat parts are connected to one another and step at least one microoptical functional unit being cut out of the interconnected flat parts.
A process of the aforementioned type is known for example from US patent U.S. Pat. No. 6,049,430. In the process described therein, two wafer-like parts are provided with optical functional elements and are joined to one another with UV-settable adhesive. The disadvantage of the aforementioned process is that a major cost must be borne to exactly position the optical functional elements of one flat part, which are made on the wafer-like parts, to those of the other flat part such that one microoptical functional unit with the desired properties is formed.
The object of the present invention is to devise a process, of the initially mentioned type, in which optically functional sections made on different flat parts can be positioned, easily in retention to one another, in the desired manner during the production process.
This result is achieved in that on the sides of the flat parts facing one another, positioning aids are formed which facilitate alignment of at least two flat parts to one another. Due to the presence of the positioning aids, the macroscopic flat parts can be aligned to one another according to desired stipulations, and the positioning aids can be chosen such that, as a result of correct alignment of the flat parts to one another, the functional sections of the respective microoptical functional unit are positioned exactly to one another.
It can furthermore be provided as depicted in the invention, that on at least one side of at least one of the parts, i.e., the side facing the other part, positioning aids are formed which can be used as cutting aids for cutting out at least one microoptical functional element from the interconnected parts. In this way the working process of subdivision of the flat parts which have been connected to one another into individual functional units is greatly simplified.
According to one preferred embodiment of this invention, on the sides of the flat parts facing one another, contact surfaces can be formed which adjoin one another after connection, the positioning aids being located on these contact surfaces. By forming the positioning aids in surfaces which adjoin one another, after moving the flat parts onto one another they can be pushed against one another until the corresponding position of the parts to one another is achieved.
Advantageously, the positioning aids contain lengthwise grooves on one of the parts and lengthwise projections which correspond to them on the other of the parts. This configuration of the positioning aids represents a very simple, but effective embodiment. Furthermore, these lengthwise grooves and lengthwise projections can be formed very economically.
The flat parts can be connected to one another using common connection methods such as cementing, soldering or welding.
In particular, it can be provided that the flat parts are made of a material which is at least partially transparent in the wavelength range of interest for the operation of the finished microoptical functional units. In this case, optically functional sections which are molded on at least one of the flat parts as lens surfaces can be formed. Advantageously, the lens surfaces can be made as cylinder lenses which extend essentially over the entire width or length of the respective flat part. These structures can be formed relatively easily in terms of production engineering.
It is also contemplated to provide mirrors, filters, prisms, or the like, as optically functional sections.
According to one preferred embodiment of this invention, the optically functional sections, made on at least one of the flat parts, in at least one direction which lies in the surface of the flat part, have properties which differ from one another relative to one optical parameter so that microoptical functional units with different properties can be cut out of the interconnected parts. Here the properties of the optically functional sections, on at least one of the flat parts can vary over the length, and/or the width, of at least one part, such that a microoptical functional unit with the desired properties can be cut out of the interconnected parts using an addressable selection process. Thus, the flat parts can be joined to one another and for a corresponding custom requirement, one or more functional units with exactly definable properties can be cut out of the wafer-like structure. One such process represents a very economical possibility for producing custom microoptical functional units.
Preferably, over the length, and/or width, of at least one of the flat parts, the index of refraction of the material used or the focal length of the optically functional sections which are made as lens surfaces can be varied. In one, or both of the aforementioned versions, for example, by means of the aforementioned addressable selection process, microoptical functional units with lenses with different indices of refraction can be selectively cut out according to the desired specification.